xxii MUTATION, MENDELISM, ETC. 



data V Such forms (it is, I submit, extremely unsafe to 

 speak of them as species) may, in the future, either 

 spontaneously or under some external stimulus break 

 up into their components, repeating the history which 

 Boulenger believes to have occurred in O. lamarckiana 

 itself. 



As this chapter was passing through the press an 

 interesting letter on Specific Stability and Mutation, by 

 Sir W. T. Thiselton-Dyer, appeared in Nature? The 

 author, after describing a number of Mutations which 

 have occurred in cultivated plants, comes to the following 

 conclusion : ' In all these cases I think we may safely 

 infer from the persistent specific stability at the com- 

 mencement of cultivation that the changes which sub- 

 sequently occur would not have occurred in nature. . . . 

 The evidence, on the other hand, that such changes 

 follow cultural conditions as a result is simply over- 

 whelming. . . .' 



4. Mutation arid the Facts of Mimicry, &c. 



The very same ideas of Discontinuity and Mutation, the 

 same revolt of the clay against the power of the potter, 

 arose again and again in the interval between the appear- 

 ance of the Origin and this modern revival. The formula 

 ' before a thing can be selected it must be ' had been 

 repeated by Cope, Semper, Eimer, and many another 

 naturalist, long before it assumed the more picturesque 

 form given to it by Bateson : ' The creature is beheld 

 to be very good after, not before its creation.' 3 



1 Carnegie Institution of Washington, 1907, I.e., p. 89. 



2 Nov. 28, 1907, pp. 77-9. 



8 Report British Association, 1904, p. 578: also on p. 577: 

 ' Selection is a true phenomenon ; but its function is to select, not to 

 create.' 



